The term “LIDAR” refers to a technique for measuring distances of visible surfaces by emitting light and measuring properties of the reflections of the emitted light.
A LIDAR system has at least one light emitter and a corresponding light sensor. The light emitter may comprise a laser that directs light in the direction of an object or surface. The light sensor may comprise a photodetector, such as a photomultiplier or avalanche photodiode (APD), that converts light intensity to a corresponding electrical signal. Optical elements such as lenses may be used in the light transmission and reception paths to focus light, depending on the particular nature of the LIDAR system.
A LIDAR system has signal processing components that analyze reflected light signals to determine the distances to surfaces from which the emitted laser light has been reflected. For example, the system may measure the “flight time” of a light signal as it travels from the laser, to the surface, and back to the light sensor. A distance is then calculated based on the flight time and the known speed of light.